Hob cutters: LMT service provides permanent performance advantage
Kownatzki’s product range is very large. The gearwheel experts produce many different types of spur gears, worm gears, sprocket wheels and crown wheels. They also make worm, spline and pinion shafts and complete transmission units. The diameters of these gearwheels ranges from 20 to 2,000 millimetres and unit weights can even reach 10 tonnes. “Ultimately, however, the same performance promise applies to all components: every gearwheel is made to high precision and with reliable delivery dates. Of course, the tools used have to do justice to these requirements because production reliability and component quality also depend on them,” explains Managing Director Michael Kownatzki.
- Wide product range: Kownatzki in Wehr produce many different types of toothed components. Its products can weigh up to ten tonnes.
Nanosphere offers convincing advantages
Kownatzki now relies on LMT Fette Nanosphere hob cutters – and is profiting from a true quantum leap in performance: “Using the new Nanosphere coating at Kownatzki has enabled us to increase tool life by a third – and that with significantly higher cutting speeds. The successes of the Nanosphere coating are considerable, especially in the high modulus sector. However, success depends crucially on reconditioning, because, of course, this performance advantage mustn’t be permanently lost after the tool begins to wear,” says Andreas Winkler of LMT field sales. The decisive factor for all users is that the Nanosphere coating system allows LMT to guarantee hob cutters can be reconditioned to the standard of new tools throughout their entire life cycle. “That means much more than simply reducing our customers’ tool costs. The hob cutters’ consistently high performance also ensures the highest level of production reliability,” explains Franz Stückle, the man at LMT responsible for providing this all-round service to customers.
Coordinated procedure
Overall, the service cycle between Kownatzki and LMT is ideally coordinated and involves clearly defined processes. After tools are collected, experts examine each one at the LMT service centre in Karlsruhe and determine how much material needs to be removed when grinding the cutting edge. Then the hob cutter is sharpened, demurred and recoated. “Of course, the customer also profits from our knowledge of LMT tools. We are very familiar with the tool geometries used by customers. Decoating, regrinding and cutting edge pretreatment on a scale of a hundredth of a millimetre produces a fundamental improvement and pays off in terms of increased performance,” explains Stückle.
- A coating machine at the LMT service centre in Karlsruhe and a module 16 hob cutter before coating with Nanosphere.
Raising component quality
Ultimately, reconditioning to original quality also increases production quality. The reasons are self-evident: conventionally coated hob cutters that no longer achieve initial levels of performance after reconditioning or whose surface geometry has changed as a result of a new coating can generate undesirable component tolerances when machining with a second or third “lease of life”. “We can prevent that with Nanosphere hob cutters, because they always come back to us in the same condition. The overall quality of the gearwheel geometries we achieve has definitely improved,” confirms Axel Felber, the man responsible for the production of large gearwheels at Kownatzki.
Background: Kownatzki
Based in Wehr in southern Germany, Kownatzki is an owner-managed family business that was founded in 1965 by twin brothers Werner and Günter Kownatzki and now employs some 100 people. Michael and Jürgen Kownatzki, the sons of the company’s founders, became managing partners in 2008. The firm specializes in the manufacture of high-quality components with complex geometries – both one-off and volume products – for use in the drive technology sector.